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ADS8568 power supply problem

Justinas Zdanevicius
Prodigy 90 points
Other Parts Discussed in Thread: ADS8568

Hello,

I have made a breakboard for testing the ADS8568 with my Tiva launchpad.

I have no problems when AVDD=DVDD (3.3V or 5V). But when DVDD < AVDD, the ADC chips heats up and becomes very hot. According to the datasheet it is ok to keep AVDD > DVDD. My analog and digital grounds are connected at one point is it because of that?

  • 0
    TI__Guru**** 175111 points

    Hi Justinas,

    You are correct, there should be no reason why you cannot have the AVdd separated (and greater) than the DVdd input to the ADS8568 so long as the analog and digital grounds are tied together.  Can you possibly provide a schematic showing your connections?  Are your power supply grounds tied back to the ground reference of the TIVA launchpad?

  • 0 in reply to Tom Hendrick
    Prodigy 90 points

    Yes, power supply grounds are tied to the TIVA ground. I think I found the problem myself: ~PAR/SER and ~STBY pins are connected to the AVDD, not the DVDD in the breakboard. I think this causes excessive heating... I am surprised that device is working after all!!!